su: add option to keep console open on shell exit

The '-N' option keeps the console window open after the elevated
shell exits.

Previously this was achieved by passing the '-s' option along with
'-c'.  Recent changes allow scripts to be run without using '-c'
so a new mechanism is required.

su passes the '-N' flag to the shell.  This causes the shell to
issue a prompt and wait for user input when it exits.

Costs 200-204 bytes.

1 files changed, 11 insertions, 6 deletions

diff --git a/loginutils/suw32.c b/loginutils/suw32.c
index b0fb26442..236d36a77 100644
--- a/loginutils/suw32.c
+++ b/loginutils/suw32.c
@@ -16,12 +16,13 @@
 //kbuild:lib-$(CONFIG_SUW32) += suw32.o
 
 //usage:#define suw32_trivial_usage
-//usage:       "[-W] [root]\n"
-//usage:       "or:    su [-W] -c CMD_STRING [[--] root [ARG0 [ARG...]]\n"
-//usage:       "or:    su [-W] [--] root [arbitrary sh arguments]"
+//usage:       "[-NW] [root]\n"
+//usage:       "or:    su [-NW] -c CMD_STRING [[--] root [ARG0 [ARG...]]\n"
+//usage:       "or:    su [-NW] [--] root [arbitrary sh arguments]"
 //usage:#define suw32_full_usage "\n\n"
 //usage:       "Run shell with elevated privileges\n"
 //usage:     "\n    -c CMD  Command to pass to 'sh -c'"
+//usage:     "\n    -N      Don't close console when shell exits"
 //usage:     "\n    -W      Wait for shell exit code"
 
 #include "libbb.h"
@@ -29,7 +30,8 @@
 
 enum {
         OPT_c = (1 << 0),
-        OPT_W = (1 << 1)
+        OPT_N = (1 << 1),
+        OPT_W = (1 << 2)
 };
 
 int suw32_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
@@ -41,7 +43,7 @@ int suw32_main(int argc UNUSED_PARAM, char **argv)
         char *bb_path, *cwd, *q, *args;
         DECLARE_PROC_ADDR(BOOL, ShellExecuteExA, SHELLEXECUTEINFOA *);
 
-        opt = getopt32(argv, "c:W", &opt_command);
+        opt = getopt32(argv, "c:NW", &opt_command);
         argv += optind;
         if (argv[0]) {
                 if (strcmp(argv[0], "root") != 0) {
@@ -78,8 +80,11 @@ int suw32_main(int argc UNUSED_PARAM, char **argv)
         free(q);
         free(cwd);
 
+        if (opt & OPT_N)
+                args = xappendword(args, "-N");
+
         if (opt_command) {
-                args = xappendword(args, "-s -c");
+                args = xappendword(args, "-c");
                 q = quote_arg(opt_command);
                 args = xappendword(args, q);
                 free(q);